Telephone system



Oct. 12, 1937. s, PETERSON 2,095,712

TELEPHONE SYSTEM Filed Feb. 5, 1936 BANKS CON N.

BAgIKS CONN.

TO LINE EQUIFMENT Ill-i INVENTOR. EDWARD S. PETERSON ATTORNEY.

Patented Oct. 12, 1937 UNITED STATES steam TELEPHONE SYSTEM Edward S.Peterson, Elmwood Park, Ill., assignor, by mesne assignments, toAssociated Electric Laboratories, Inc., Chicago, 111., a corporation ofDelaware Application February 3, 1936,Serial No. 62,084

13 Claims.

The present invention relates in general to telephone systems, but morein particular to an arrangement for giving a telephone subscriber aspecial type of service which will be referred to hereinafter astransfer service. A subscriber having this service is able to bringabout a switching operation at the exchange, in effect for any desiredperiod, which causes all calls intended for his telephone to be divertedto another telephone. The object of the invention is a new and improvedarrangement of the foregoing character. I

The invention is especially useful for doctors, lawyers, and otherprofessional people who are frequently absent from their offices and whodo not wish to incur the expense of employing a secretary to answertelephone calls. It is also useful in the case of a doctor, for example,who has a secretary or attendant to answer calls during the day time,but desires to keep himself accessible to his patients at nights, whenthe office is unattended. In these and other cases the subscribersconcerned, by contracting for the transfer service, are able to usetheir residence telephones for answering ofiice calls and thus securethe equivalent of 24-hour service in connection with their officetelephone numbers.

The invention will be described more in detail with reference to theaccompanying drawing, which is a diagrammatic circuit drawing showingthe apparatus involved and the manner in which it is installed in atypical telephone system. Referring to the drawing, the reference letterA represents an automatic telephone station assumed to be at the officeof a subscriber having the transfer service. B is the residencetelephone, or any other telephone to which calls are to be transferred.The main distributing frame is indicated by reference letters MDF, andthe intermediate distributing frame by the reference letters IDF. Atransfer equipment, comprising four relays 3ll33, is indicated at TS.

The usual connections for a subscribers line are shown in the case ofthe line of substation B. The line 2 is cross-connected by means of aduplex jumper d at the MDF to a pair of protectors 5, indicated forconvenience as fuses. From the protectors a cable pair leads to the lineside of the IDF, where the line equipment is permanently connected. Theforegoing are the connections required for outgoing service. The line isconnected up for incoming service by running a jumper 6 from theterminal set on the line side of the IDF, to the set of terminals on theconnector bank side which corresponds to the assigned telephonenumber.This jumper has three conductors (triplex) so as to connect throughthethird wire, used for testing and busying purposes. The foregoing iscommon practice and is wellunderstood.

The transfer equipment, comprising a plurality of units such as TS, ispreferably mounted as part of the automatic switchboard, on regularswitch or repeater shelves, or on separate uprights. It is advisable toprovide for jack mountingpusing the ordinary male and female jacks suchas are used for automatic switches, although this is not essential.Assuming that jack mounting is used, each unit will require eleven jackconnections, those for unit TS being indicated at 8 and 9. All thefemale jacks of jack connections such as 8' are permanently connected bycable to an extra group of protectors on the MDF, one pair of this groupbeing indicated at I. .All the female jacks of jack connections such as9 are permanently connected by cable to an extra group of terminals suchas ill on the IDF. Thisextra group of terminals may be either on theline side, as shown, or on the connector bank side.

Station A is connected up for transfer service in the manner shown inthe drawing. The old jumper on the MDF which connected line E toprotector pair M has been removed and a new jumper 3 has'beenrun,connecting line I to the pair of protectors l which is associated withthe transfer unit TS. At the IDF the old jumper, corresponding to 6, hasbeen removed also, and three new jumpers l I, I2, and id, have been runfromthe particular nine terminals of group In which are associated withtransfer unit TS. Jumper I l serves to connect the terminals M43 withthe terminals on the connector bank side of the IDF whichare associatedwithv the office telephone number. Jumper l2 connects the terminals 4446with the residence line, that is, the line of telephone station B. Thisjumper may pickup the line of station B at the connector bank side ofthe IDF as shown, or at the line side. Jumper l3 connects the terminals4'l49 with the line equipment associated with station A.

It will be assumed now that the key at station A is normal, as will bethe case if the subscriber or attendant is present. If the receiver isremoved to makean outgoing call the transmitter and receiver are bridgedacross line I, closing a circuit for relays 3i and 33 in series. Boththese relays operate. At 39 relay 3| connects terminal 49 with terminal43 via 53, thus connecting through the third wire 56 associated with theline equipment to the third wire 51 extending to the connector bankcontactsets of station A. At 38 relay 3! attempts to close a circuit forrelay 32, but fails to do so because relay 33 opens the circuit of relay32 atAIl. At 50 relay 33 places a bridge across the'line conductors 54and 55, extending via 4'! and 48 to the line equipment of station A,thus placing the line in calling condition.

The system may use either line switches or finders to extend callinglines to idle trunk lines. In any case as soon as an idle trunk isconnected with ground is extended back over the third wire 56, makingthe line busy to the connectors, and operating relay 30. Relay shuntscontacts 33 at 31, and at and 33 disconnects line I from V relays 3! and33 and extends it through to line,

third wire 51, and relay 30 and'the' cut-off relay fall back. 7

' by ,disconnectingthe three terminals 4|, 42, and

conductors 54 and 55.. Relays 3| and 33 now fall back, but withouteffect. The automatic equipon the third wire 56 to 'hold relay 30inoperated I position. The callis completed bydialling in the usualmanner. The connection is released by hanging up the receiver at stationA, which permits the automatic switches to restore. This removes groundfrom the third wire 56 and allows relay 33 to fall back.

When station A is called, the connector in use places ground on thethird wire 51,, thereby closing a circuit over the third strand ofjumper II, 43, 53, and winding of relay 30 to battery. Relay 3!!accordingly energizes and connects conductors E i and 55 through to thecalled line, disconnecting relays 3| and 33 at the same time. Relay 30also connects the third wire 51 through to third wire 55 at 31, andground is thus extended to the line equipment of station A, where thecut-off relay is operated in the usual manner. Ringing current is nowtransmitted over line I from the connector to operate the bell attelephone A, and the. call is answered in the usual manner. theconnector is released, ground is removed from It will now be assumedthat the telephone station A is left unattended for a while. Beforeleaving the premises the subscriber or attendant will operate the key K,which may be in thebase of the telephone or at any convenient place. Thekey is of the type which stays in operated position. If desired thereceiver may be removed and it off after the key has been operated, asan aid to the subscriber in reminding him torestore the key when hereturns.

When key K is operated it grounds the nega- I tive side of line I andoperates relay 3|. Relay 33 remains deenergized, whether the receiver isremoved or not. a circuit at 38 for relay 32. The latter relay, onenergizing, operates contacts 5I,'52,,and 53, thered3 from their normalassociationwith line I and connecting them instead with terminals 44,i5, and 46, which are associated with line 2 overthe triplex juniper I2.Relays 3| and 32 remain energized while key K remains actuated, or whilethe telephone station A is left unattended.

If telephone A is called during this period, the. connector in useplaces a ground on third wire 5'E, which is now connected with thirdwires 58 and 59. at 53. The grounding of third wire 58 operates thecut-01f relay of the line equipment When On energizing, relay .3 Icloses,

associated with line 2, the line of telephone station B, and thegrounding of 59 guards the line against intrusion by another call.Ringing current is now transmitted from the connector via the bankcontacts of station A, the jumper II, contacts 5I and 52 of relay 32,and jumpers I2, 5, and 4 to line 2, operating the bell at telephone B.The call is answered at that telephone in the appropriate manner, and sofar as the calling party is concerned the service is the same as if thecall had been answered at telephone 2.

It will be evident that while the transfer relay 32 is in operatedposition an office call will make the residence line busy, while a callto the residence line will make the office line busy. This limitation isinherent from the nature of the system and is not a particular drawbackfrom the standpoint of selling the service. As regards the 1 possibleloss of a residence call due to a call on the office line, thesubscriber is willing to subordinate his residence service to themaintaining of continuous service on the office line; and as regards thepossible blocking of an ofiice call by reason of the residence linebeing in use the subscriber can give instructions su tably restrictingthe use of the residence phone while the transfer unit is intransferring condition.

It will be assumed now that the subscriber returns to his office. Thereceiver is replaced at telephone A, if it was left off, and key K isrestored. Relay 3I accordingly falls back and breaks the initialenergizing circuit of relay 32, which falls back also unless theresidence telephone B is engaged in a call. In the latter event relay 32is locked up to the third wire through contacts 60, and remainsenergized until the call is over with. This provision is made becausethe call in which telephone B is engaged may be a call intended fortelephone A, being answered at telephone B, and if relay 32 werepermitted to fall back while conversation was going on the call would beinterrupted.

If the receiver is removed at telephone A to make an outgoing call whilerelay 32 is locked up, relays 3! and 33 energize and the latter relayinitiates the call by placing a bridge across conductors 54 and 55 at 50as previously described. This operates the calling equipment, lineswitch or finder, and ground is applied to third wire 58, operatingrelay 3!] by way of 39. Relay 33 looks itself to the third wire at 3'!and disconnects relays SI and 33. During the short interval in whichrelay 33 is operated it makes a test to ascertain if relay 32 is lockedup due to a call intended for telephone A, or due toa regular outgoingor incoming call involving telephone B.

Explaining this operation, when relay 33 energlzes it opens the multipleconnection between the third wires of lines I and 2 at the springscontrolled by armature 6|, and at the same time by means of armature GIand its working contact it grounds the third wire 58 of line 2. Thereare two cases to be considered now. In the first case relay 32 is lockedto ground on the third wire 58 or 59 of line 2, and accordingly when themultiple connection to the third wire 51 is broken relay 32 at oncefalls back and breaks its own locking circuit at 60. The ground appliedto the third wire of line 2 by the operation of relay 33 does no harm,and it is taken off at 52 as soon as relay 32 falls back. In the secondcase relay 32 is locked to ground on the third wire 5'! and of coursestays locked. The ground applied to third wire 58 by way of 52 and 5!holds the cutoff. relay of line 2 energized, and this same groundconnection on 59 maintains line 2 'in busy condition to preventintrusion by another call. When relay 33 falls back due to the operationof relay 3!] the thirdwires 58 and 59 are again joined to third wire 51and the temporary ground connection through 5! and 62 removed. Thecircuit remains in this condition, with relay 32 locked up, until theconnector maintaining ground on 5'! is released- The arrangement justdescribed is not essential but it is a desirable feature, as it providesfor automatically unlocking relay 32 responsive to an outgoing call fromstation A if the relay is locked up due to a regular call on line 2, a

call in which the transfer service is not involved.

The subscriber at station A can make use of this feature if he desiresby always momentarily removing his receiver after restoring the key K,which will insure the immediate reestablishment of incoming service tostation A, unless a transferred call is actually in progress.

If the feature of selectively unlocking relay 32 is to be left out, thesprings 6i and 62 are omitted and the front contact of spring 53 isWired direct through a jack connection 9 to terminal iii. Or in a unitlike the one shown in the drawingthe armature spring 6! can be easilyadjusted so that it will not engage its working contact. Relay 32 willthen remain; locked up after the key K is restored provided there is acall on line 2, and it cannot be unlocked until the call is released.

Another modification involves the omission of the locking contacts 6!),and may be used if the subscriber desires 'to definitely insure theimmediate restoration of incoming service at telephone A uponrestoration of key K, even though it may result in the interruption ofan office call being answered at telephone B. Ifthis modification isused, however, the subscriber should be ininstructed to promptly removehis receiver and challenge on the line after the key K is restored, sothat if a transferred call was in progress he can take it over.Explaining this a little further, it will be seen that when relay 32falls back on restoration of the key, the third Wire 51, which isgrounded if a transferred call is in progress at the time, will beswitched back at 53 to its normal connection with relay 30, operatingthis relay. Relay 3E] closes the talking circuit at 35 and 36 and whenthe subscriber at station A comes on the line he can pick up the call.

The transfer equipment is adapted for use in connection with other typesof telephone systems than the one specifically referred to herein. Onesystem in extensive use is similar to the one described, except that theconnector bank cables and the line equipment cables have their positionsinterchanged at the IDF. Obviously the transfer units can be used inthis type of system by merely reversing the jumpers such as H and I3 atone end or the other. Other systems are known in which no IDF is usedand the calling and called branches of the lines are permanentlyconnected. These permanent connections, of course, have to be opened up,by unsoldering at the cable terminals, in order to insert the transferunits. In any case the units will work in manual systems as well as inautomatic systems. In manual systems, however, the arrangement isgenerally such that the third wire of an engaged line is connected tobattery instead of ground to make the line busy and to operate thecut-off relay. In order to accommodate the transfer units to thisarrangement the relays such as 30 are connected to ground instead of tobattery.

The invention having been described, that which is believed to be newand for which the protection of Letters Patent is desired will bepointed out in the appended claims.

What is claimed is:

1. In a telephone system, an ofiice line, a residence line, a device atthe station on the oifice line adapted for sustained operation to modifythe line circuit'to indicate an unattended condition so long as saiddevice remains operated, and means at the exchange sensitive to themodified line circuit and effective invresponse thereto to divert callsintended for the ofiice line to the residence line.

2. In a telephone system, a subscribers line extending to the exchange,a branch over which the line is called, a transfer relay for switchingsaid branch into multiple connection with the corresponding branch ofanother line, and controlling means for said relay effective to operateit if one side of the line is grounded at the subscribers station andnot operate it when the receiver is removed.

3. In a telephone system, a subscribers line extending to the exchange,calling and called branches normally disconnected from the line, atransfer relay for switching the called branch into association withanother line, means for opcrating said relay responsive to grounding theline at the subscribers station, means responsive to the removal of thereceiver when the line is ungrounded for initiating a call over thecalling branch, and means responsivev to the initiation of the call forextending the line through to the calling branch.

4. In a telephone system, a subscribers line extending to the exchange,a branch of the line over which the line is called, a transfer relay forswitching said branch into multiple connection with the correspondingbranch of another line, means for energizing said relay from thesubscribers station, and means for holding said relay independent ofsaid energizing means providing the latter is released by the subscriberat a time when the said first branch is in use.

5. In a telephone system, a subscribers line extending to the exchange,a branch over which the line is called, a transfer relay for switchingsaid branch into multiple connection with the corresponding branch ofanother line, means at the subscribers station for energizing saidrelay, means for holding said relay after the said energizing means isreleased provided either of said branches is in use, and meansresponsive to the removal of the receiver at the subscribers station fortesting to ascertain which branch is in use and for rendering saidholding means ineffective if the branch in use is the branch associatedwith the other line.

6. In a telephone system, a plurality of transfer units, each unitincluding a relay for directly switching the conductors over whichaccess is had to a line when called into multiple connection with thecorresponding conductors of another line, permanent cable connectionsbetween said units and the main and intermediate distributing frames,whereby any subscribers line may be equipped with one of said units byrunning jumpers at said frames, and means at the station on each line soequipped for maintaining the relay in the associated unit energizedwhile the subscriber is absent from the station.

'7. In a telephone system, a subscribers line,

, normallyvdis'connected calling branch extending necting thesubscribers line to the line conductors of the calling and calledbranches, and for connecting said test conductors together.

8. In' a telephone system, a subscribers line, a branch of said lineaccessible. to connector switches, a second branch extending to lineequipment, test conductors included in said branches normallydisconnected from each other, a relay energized over the test conductorof the connector branch when the line is called, and contacts on saidrelay for connecting said test conductors together.- r

9. In a telephone system, a subscribers line, a

to line equipment for initiating outgoing calls, two relays normallybridged across said line and responsive to the removal of the receiver,contacts on one line relay for initiating, the operation of said lineequipment, a third relay connected'to the test conductor of said callingbranch by the other of said line relays, said third relay beingenergized over said test conductor responsive to the operation of saidline equipment, and contacts on said third relay forlocking I itself tosaid test conductor, for disconnecting said line relays, and forconnecting the subscribers line with said calling branch.

.10. In a telephone system, a subscribers line, a called'branch for saidline normally disconnected from said line, a relay energized when the aline is called to connect said called branch to the line; a-transferrelay controlled over said line from the subscribers station, andcontacts on said transfer relay effective when the relay is in energizedcondition for maintaining said called branch connected in multiple toanother subscribers line and for preventing the energization of saidfirst relay when the said first line is called.

11. In a telephone system, a subscribers line, a transfer relay fordiverting calls intended for said line to another line, two line relaysnormally bridged across said line, one relay being responsive togrounding thev line at the station and both relays being responsive tobridging the line at the station, and a circuit for said transfer relaycontrolled jointl by said relays. 7 u

12. In a telephone system, a subscribers line,

a a key at the station on said line, a relay at the exchange heldenergized over one side of the line while said key is in operatedposition, a transfer relay for diverting calls intended for said line toanother line, a circuit for said transfer relay closed by said firstrelay, another relay energized over said first line responsive to theremoval of the receiver, and contacts on said last mentioned relay fordisabling said circuit to deenergize said transfer relay.

13. In a telephone system, a main frame on which subscribers lines areterminated, an intermediate frame on which calling and called linebranches are terminated, a transfer unit comprising a transfer relay anda plurality of controlling relays, connections from said unit to a setof terminals on said main frame and to three sets of terminals on saidintermediate frame, a jumper connecting said first set of terminals to asubscribers line, and three jumpers connecting said three sets ofterminals, respectively, with the called branch of said subscribersline, the calling branch of said subscribers line, and anothersubscribers line, the said unit andconnections including said jumpersconstituting means whereby 'the station on said first line can extendand receive calls and whereby incoming calls can be diverted to saidother line at times when the station is unattended.

EDWARD S. PETERSON.

